Stereochemistry of Transmetalation of Alkylboranes in Nickel-Catalyzed Alkyl-Alkyl Cross-Coupling Reactions

Deuterium-labeled alkylborane reagents 2a and 2b were prepared and subjected to cross-coupling reactions in the presence of a nickel catalyst. NMR analysis of the products indicates that transmetalation from boron to nickel proceeds with retention of configuration. These results demonstrate that alkylnickel intermediates are configurationally stable under Suzuki cross-coupling conditions.